"Final Fantasy Crystal Chronicles - Rings Of Fate" for the Nintendo DS is due to be released on 28/3/08
ChoicesUK has it for Pre-Order for £16.99 (inc Del.)
You can get cashback from the usual sites (e.g. 5% from Quidco making it just £16.14)
Next best UK price seems to be £24.43 from TheHut.
FINAL FANTASY CRYSTAL CHRONICLES: Ring of Fates is a high quality and unique action adventure, in the universe of FINAL FANTASY, the worlds number one RPG brand. Using real-time, action-based control, immersive 3D graphics, multi-player gameplay for up to four friends and use of the innovative Nintendo DS touchscreen players everywhere can experience the story of innocent twins caught in an action-packed, fateful and fantastic adventure.